Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA.
Biomaterials. 2013 Mar;34(9):2213-20. doi: 10.1016/j.biomaterials.2012.12.002. Epub 2013 Jan 2.
Bridges implanted into the injured spinal cord function to stabilize the injury, while also supporting and directing axon growth. The architecture of the bridge is critical to its function, with pores to support cell infiltration that integrates the implant with the host and channels to direct axon elongation. Here, we developed a sucrose fiber template to create poly(lactide-co-glycolide) multiple channel bridges for implantation into a lateral hemisection that had a 3-fold increase in channel number relative to previous bridges and an overall porosity ranging from approximately 70%-90%. Following implantation into rat and mouse models, axons were observed within channels for all conditions. The axon density within the bridge increased nearly 7-fold relative to previous bridges with fewer channels. Furthermore, increasing the bridge porosity substantially increased the number of axons, which correlated with the extent of cell infiltration throughout the bridge. Analysis of these cell types identified an increased presence of mature oligodendrocytes within the bridge at higher porosities. These results demonstrate that channels and bridge porosity influence the re-growth of axons through the injury. These bridges provide a platform technology capable of being combined with the delivery of regenerative factors for the ultimate goal of achieving functional recovery.
植入损伤脊髓的桥接体起到稳定损伤部位的作用，同时还支持和引导轴突生长。桥接体的结构对于其功能至关重要，其具有用于支持细胞渗透的孔，以将植入物与宿主整合，以及用于引导轴突延伸的通道。在这里，我们开发了一种蔗糖纤维模板，用于创建聚（乳酸-共-乙醇酸）多通道桥接体，用于植入横向半切模型，与以前的桥接体相比，通道数量增加了 3 倍，整体孔隙率约为 70%-90%。在将其植入大鼠和小鼠模型后，在所有条件下都可以观察到通道内有轴突。与通道较少的先前桥接体相比，桥接体内的轴突密度增加了近 7 倍。此外，增加桥接体的孔隙率会大大增加轴突的数量，这与整个桥接体中细胞渗透的程度相关。对这些细胞类型的分析表明，在更高的孔隙率下，桥接体内成熟少突胶质细胞的存在增加。这些结果表明，通道和桥接体的孔隙率会影响损伤部位轴突的再生。这些桥接体提供了一种平台技术，可与再生因子的递送来结合，以实现功能恢复的最终目标。
